STP1092

    A Computer-Controlled Automated Test System for Fatigue and Fracture Testing

    Published: Jan 1990


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    Abstract

    A computer-controlled system consisting of a servohydraulic test machine, an in-house designed test controller, and a desktop computer has been developed for performing automated fracture toughness and fatigue crack growth testing both in the laboratory and in hot cells for remote testing of irradiated specimens. Both unloading compliance and dc-potential drop can be used to monitor crack growth. The test controller includes a dc-current supply programmer, a function generator for driving the servohydraulic test machine to required test outputs, five measurement channels (each consisting of low-pass filter, track/hold amplifier, and 16-bit analog-to-digital converter), and digital logic for various control and data multiplexing functions. The test controller connects to the computer via a 16-bit wide photoisolated bidirectional bus. The computer, a Hewlett-Packard Series 200/300, inputs specimen and test parameters from the operator, configures the test controller, stores test data from the test controller in memory, does preliminary analysis during the test, and records sensor calibrations, specimen and test parameters, and test data on flexible diskette for later recall and analysis with measured initial and final crack length information. During the test, the operator can change test parameters as necessary.

    Keywords:

    computers, fatigue (materials), crack growth, fracture toughness, test controller, compliance, dc-potential, J, -integral, multichannel test controller, J-R, curve, analog-to-digital converter, photo-isolation, complementary metal oxide semiconductor, clip gage, automation, interface, fracture testing, fatigue testing


    Author Information:

    Nanstad, RK
    Group leader, metallurgical engineer, and principal technologist, Oak Ridge National Laboratory, Oak Ridge, TN

    Alexander, DJ
    Group leader, metallurgical engineer, and principal technologist, Oak Ridge National Laboratory, Oak Ridge, TN

    Swain, RL
    Group leader, metallurgical engineer, and principal technologist, Oak Ridge National Laboratory, Oak Ridge, TN

    Hutton, JT
    Development engineer and instrument technician, Oak Ridge National Laboratory, Oak Ridge, TN

    Thomas, DL
    Development engineer and instrument technician, Oak Ridge National Laboratory, Oak Ridge, TN


    Paper ID: STP25027S

    Committee/Subcommittee: E08.03

    DOI: 10.1520/STP25027S


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